I have an issue with printing "two-up" labels on a Zebra 2844 TT printer. The label has 5 lines of text. All the text is well within margins. Page setup points to correct printer and label template, Across, then Down, and Fixed Margins unchecked.
The issue is the first pair of labels print okay. The second label pair prints the fifth line one line low so the last line of text ends up on the non-print area. The third pair is skipped altogether. The remaining records print okay until the end. All the records are printed - i.e. no record is skipped, just the second and third pair of labels is wasted.
My work-around has been to insert dummy records at the beginning of each print cycle. It's a waste but at least I get all the records printed correctly.
Since I do a lot of one-off printing, there is considerable waste as each label cost $.05/label.
It sure sounds like you do not have the Body sized correctly. You can tell if the amount off is increasing or decreasing between each label. Do you have automatic sliding parts going on or something like that?